Nucleosome
Structure responsible in part for the compactness of a chromosome. Each nucleosome consists of a sequence of DNA wrapped around a core of histone (a type of protein).
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A localized aggregation of histone and DNA that is evident when chromatin is in the uncondensed stage. SYN: nu body. [nucleo- + G. soma, body]

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nu·cleo·some -.sōm n any of the repeating globular subunits of chromatin that consist of a complex of DNA and histone and are thought to be present only during interphase
nu·cleo·so·mal .n(y)ü-klē-ə-'sō-məl adj

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nu·cleo·some (nooґkle-o-sōm) [nucleo- + -some] the primary structural unit of eukaryotic chromatin; a complex of histone and DNA seen with the electron microscope as one of the “beads on a string” characteristic of the partially unfolded chromatin in low ionic strength buffer. It comprises a segment of approximately 146 base pairs of DNA wrapped twice around an octamer core of two each of the histones H2A, H2B, H3, and H4, and is connected to each adjacent nucleosome by a short linker DNA segment. The nucleosomes are further compacted into a 30-nm diameter fiber, the structure of which remains controversial; the classic model describes it as a helical solenoid (q.v.).

Medical dictionary. 2011.

Look at other dictionaries:

  • Nucleosome — Nucléosome Structure d un nucléosome. On distingue les extrémités N terminales des histones se projetant à l extérieur de la partie globulaire du nucléosome Un nucléosome est un complexe de protéines, octamère d histones, de structure 2x(H2A, H2B …   Wikipédia en Français

  • nucléosome — [ nykleozom ] n. m. • 1975; de nucléo et some ♦ Biol. Structure élémentaire de la chromatine, consistant en environ deux cents paires de bases d A. D. N. et de deux copies de quatre histones différentes. nucléosome [nykleosom; nykleozom] n. m.… …   Encyclopédie Universelle

  • nucleosome — nucleosome. См. нуклеосома. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • nucleosome — [no͞o′klē ō sōm΄, nyo͞o′klē ō sōm΄] n. the basic structural unit of chromatin in eukaryotes, composed of eight histone molecules wrapped by a segment of DNA: nucleosomes occur at intervals along a continuous strand of DNA …   English World dictionary

  • Nucleosome — Nucleosomes are the basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound around a histone protein core.[1] This structure is often compared to thread wrapped around a spool.[2] Nucleosomes form the fundamental repeating …   Wikipedia

  • Nucléosome — Le nucléosome est un complexe d’ADN et de protéines qui constitue l’unité de base de la chromatine. Il représente le premier niveau de compaction de l’ADN. En contrôlant l’accessibilité du double brin d’ADN, il est directement impliqué dans la… …   Wikipédia en Français

  • nucleosome — noun Date: 1962 any of the repeating globular subunits of chromatin that consist of a complex of DNA and histone • nucleosomal adjective …   New Collegiate Dictionary

  • nucleosome — (nu kle o sōm ) A complex of histones and DNA found in eucaryotic chromatin; the DNA is wrapped around the surface of the beadlike histone complex …   Dictionary of microbiology

  • nucleosome — Repeating units of organization of chromatin fibres in chromosomes, consisting of around 200 base pairs, and two molecules each of the histones H2A, H2B, H3 and H4. Most of the DNA (around 140 base pairs) is believed to be wound around a core… …   Dictionary of molecular biology

  • nucleosome — /nooh klee euh sohm , nyooh /, n. Cell Biol. any of the repeating subunits of chromatin occurring at intervals along a strand of DNA, consisting of DNA coiled around histone. [1960 65; NUCLEO + SOME3] * * * …   Universalium

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